1/* ----------------------------------------------------------------------- *
2 *
3 *   Copyright 2001-2008 H. Peter Anvin - All Rights Reserved
4 *
5 *   This program is free software; you can redistribute it and/or modify
6 *   it under the terms of the GNU General Public License as published by
7 *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
8 *   Boston MA 02111-1307, USA; either version 2 of the License, or
9 *   (at your option) any later version; incorporated herein by reference.
10 *
11 * ----------------------------------------------------------------------- */
12
13/*
14 * fat.h
15 *
16 * Basic data structures for a FAT filesystem
17 */
18
19#ifndef FAT_H
20#define FAT_H
21
22#include "ulint.h"
23
24/* The poor excuse FAT has for a superblock -- in the boot sector */
25struct fat_bootsect {
26    le8_t bsJump[3];		/* Jump to code */
27    char bsOemName[8];		/* Formatting program */
28    le16_t bsBytesPerSec;	/* Bytes/sector */
29    le8_t bsSecPerClust;	/* Sectors/cluster */
30    le16_t bsResSectors;	/* Reserved sectors */
31    le8_t bsFATs;		/* Number of FATs */
32    le16_t bsRootDirEnts;	/* Number of entries/root directory */
33    le16_t bsSectors;		/* Number of sectors [1] */
34    le8_t bsMedia;		/* Magic media type byte */
35    le16_t bsFATsecs;		/* Sectors/FAT */
36    le16_t bsSecPerTrack;	/* Sectors/track */
37    le16_t bsHeads;		/* Number of heads */
38    le32_t bsHiddenSecs;	/* Number of hidden sectors */
39    le32_t bsHugeSectors;	/* Number of sectors [2] */
40    union {
41	/* FAT12/16 */
42	struct {
43	    le8_t bsDriveNumber;	/* Drive number */
44	    le8_t bsReserved1;	/* Reserved */
45	    le8_t bsBootSignature;	/* 0x29 */
46	    le32_t bsVolumeID;	/* Volume serial number */
47	    char bsVolumeLabel[11];	/* Volume name */
48	    char bsFileSysType[8];	/* File system type */
49
50	    le8_t bsCode[448];	/* Boot sector code */
51	} fat16;
52
53	/* FAT32 */
54	struct {
55	    le32_t bpb_fatsz32;	/* Sectors/FAT */
56	    le16_t bpb_extflags;	/* Extended flags */
57	    le16_t bpb_fsver;	/* Filesystem version */
58	    le32_t bpb_rootclus;	/* Root directory cluster */
59	    le16_t bpb_fsinfo;	/* FSINFO sector number */
60	    le16_t bpb_bkbootsec;	/* Backup boot sector (superblock) */
61	    char bpb_reserved[12];
62
63	    /* Same shit, different offset! */
64	    le8_t bsDriveNumber;	/* Drive number */
65	    le8_t bsReserved1;	/* Reserved */
66	    le8_t bsBootSignature;	/* 0x29 */
67	    le32_t bsVolumeID;	/* Volume serial number */
68	    char bsVolumeLabel[11];	/* Volume name */
69	    char bsFileSysType[8];	/* File system type */
70
71	    le8_t bsCode[420];	/* Boot sector code */
72	} fat32;
73    } u;
74
75    le16_t bsSignature;		/* 0xAA55 */
76};
77
78#define BS_BOOTSIGNATURE	0x29
79#define BS_SIGNATURE		0xAA55
80
81/* A FAT filesystem directory entry */
82
83struct fat_dirent {
84    le8_t name[11];		/* Mangled filename */
85    le8_t attribute;		/* File type/attribute */
86    le8_t caseflags;		/* VFAT: case for basis and extension */
87    le8_t ctime_ms;		/* ms of creation time */
88    le32_t ctime;		/* Creation time */
89    le16_t atime;		/* Date portion (high 16 bits) of atime */
90    le16_t clusthi;		/* FAT32: high 16 bits of cluster */
91    le32_t mtime;		/* Modification time */
92    le16_t clustlo;		/* First cluster pointer */
93    le32_t size;		/* File size (bytes) */
94};
95
96/* A VFAT filesystem continuation entry */
97struct fat_vfat_slot {
98    le8_t id;			/* Sequence number for slot */
99    le16_t name0[5];		/* 5 characters */
100    le8_t attribute;		/* Attribute byte */
101    le8_t reserved;		/* Reserved, MBZ */
102    le8_t alias_csum;		/* Short name checksum */
103    le16_t name5[6];		/* 6 characters */
104    le16_t firstclust;		/* MBZ */
105    le16_t name11[2];		/* 2 characters */
106};
107
108#endif /* FAT_H */
109